VELOCITY PERCEPTION — CENTRALLY OR RETINALLY ORGANISED?

C ohen , R. L. Velocity perception—centrally or retinally organised? Scand. J. Psychol ., 1961, 2, 45–48.—5 subjects were asked to estimate ( a ) the relative and (6) the absolute velocities of two spots moving in a simple harmonic motion, 180° out of phase under two experimental conditions: (1) both spots projected on to bothretinas, and (2) one spot projected on to one retina and the second on to the other. Theresults were precisely the same under both conditions. This was taken as indicating that(a) the organisation of velocity perception is central rather than retinal, and ( b ) the effect of interference caused by one spot when trying to estimate the velocity of the other (the signal) is not lessened when the interference is fed into the eye other than the one receiving the signal spot.     

Statistical power analysis for one-way analysis of variance: A computer program

To facilitate the computation of statistical power for analysis of variance, Cohen developed the index of effect sizef, defined as theSD between groups divided by theSD within groups. A microcomputer program for statistical power allows the user to compute the value off in any of several ways: by specifying the mean andSD for every cell in the ANOVA; by specifying the mean value for the two extreme cells and the pattern of dispersion for the remaining cells; by estimating the proportion of variance in the dependent variable that will be explained by group membership; and/or with reference to conventions for small, medium, and large effects. The program will compute power for any single set of parameters; it will also allow the user to generate tables and graphs showing how power will vary as a function of effect size, sample size, andα.     

Mothers' use of personal pronouns when talking with toddlers

The verbal interaction of 2-year-old children (N = 46; 16 girls, 30 boys) and their mothers was audiotaped, transcribed, and analyzed for the use of personal pronouns, the total number of utterances, the child's mean length of utterance, and the mother's responsiveness to her child's utterances. Mothers' use of the personal pronoun we was significantly related to their children's performance on the Stanford-Binet at age 5 and the Wechsler Intelligence Scale for Children at age 8. Mothers' use of we in social--vocal interchange, indicating a system for establishing a shared relationship with the child, was closely connected with their verbal responsiveness to their children. The total amount of maternal talking, the number of personal pronouns used by mothers, and their verbal responsiveness to their children were not related to mothers' social class or years of education.     

Evaluation and Comparison of Three Instruments Designed to Measure Organizational Power and Influence Tactics

The purpose of the present study is to assess the internal consistency and construct validity of three instruments measuring the use of influence tactics. Instruments by Frost and Stahelski (1988) and Hinkin and Schriesheim (1989) had been developed to be psychometrically sound measures of the French and Raven (1959) bases of power. Kipnis and Schmidt (1982a) developed a new typology to measure organizational influence, the Profile of Organizational Influence Strategies (POIS). Four hundred seventy-nine undergraduate students completed these instruments to describe the influence tactics used by their supervisor. Results indicated that the Hinkin and Schriesheim instrument has greater internal consistency and a more precisely defined factor structure than the Frost and Stahelski instrument. The corresponding scales of the two instruments measuring the French and Raven power bases are not highly correlated, suggesting that the two instruments are not equivalent. Furthermore, the pattern of correlations between scales of the three instruments suggests that neither the French and Raven not the POIS typology fully represents the structure of influence tactics.     

Tests of behavior momentum in simple and multiple schedules with rats and pigeons.

Four experiments examined the relationship between rate of reinforcement and resistance to change in rats' and pigeons' responses under simple and multiple schedules of reinforcement. In Experiment 1, 28 rats responded under either simple fixed-ratio, variable-ratio, fixed-interval, or variable-interval schedules; in Experiment 2, 3 pigeons responded under simple fixed-ratio schedules. Under each schedule, rate of reinforcement varied across four successive conditions. In Experiment 3, 14 rats responded under either a multiple fixed-ratio schedule or a multiple fixed-interval schedule, each with two components that differed in rate of reinforcement. In Experiment 4, 7 pigeons responded under either a multiple fixed-ratio or a multiple fixed-interval schedule, each with three components that also differed in rate of reinforcement. Under each condition of each experiment, resistance to change was studied by measuring schedule-controlled performance under conditions with prefeeding, response-independent food during the schedule or during timeouts that separated components of the multiple schedules, and by measuring behavior under extinction. There were no consistent differences between rats and pigeons. There was no direct relationship between rates of reinforcement and resistance to change when rates of reinforcement varied across successive conditions in the simple schedules. By comparison, in the multiple schedules there was a direct relationship between rates of reinforcement and resistance to change during most tests of resistance to change. The major exception was delivering response-independent food during the schedule; this disrupted responding, but there was no direct relationship between rates of reinforcement and resistance to change in simple- or multiple-schedule contexts. The data suggest that rate of reinforcement determines resistance to change in multiple schedules, but that this relationship does not hold under simple schedules.     

Orientation asymmetry in the flanker task

Experiments 1 and 2 of this study show that when the target is either a vertical or a horizontal line, diagonal-line flankers tilted 45° either to the right or to the left have the same effect as do incongruent flankers. When the target is a diagonal line tilted either to the right or to the left, vertical- or horizontal-line flankers do not have the same effect as do incongruent flankers. Experiment 3 demonstrates that this asymmetry is not caused by the temporal-dynamic aspects of the processing. Together, these experiments suggest that there is an asymmetrical relation between diagonal lines and either vertical or horizontal lines otttside of the central focus of attention. Experiment 4 shows that despite this asymmetry in the flanker task, visual search for a vertical- or a horizontal-line target among diagonal-line distractors is not affected by the number of distractors. Possible explanations of this phenomenon are discussed.